Chemical cocktail in the blood of polar bears | Polarjournal
Polar bears live in one of the most isolated regions on earth – but are still heavily exposed to environmental toxins. (Foto: Heiner Kubny)

The king of the Arctic is still surprisingly contaminated with environmental toxins. According to new analyses, in addition to previously detected substances, many other harmful chemicals are found in polar bears’ bodies. The high concentration of some of these substances is particularly alarming. A decrease in intoxication was expected. However, this did not occur, and in fact increased.

Seals make up the main part of their diet, as well as young or weakened walruses. Well-fed polar bears eat only skin and blubber from freshly killed prey, the rest remains lying. Weaker bears or polar foxes, but also carrion-eating seabirds like seagulls, scavange on the remains. (Image: Heiner Kubny)

Almost everywhere, humans and animals are potentially exposed to the harmful chemicals that enter the food chain from the environment. Even substances that have long been banned, such as the insecticide DDT and the carcinogenic PCBs, can still be detected basically all over the world today; even in the Arctic, such long-lived organic pollutants can be found.

The substances reach the remote polar region mainly via air and ocean currents, to the detriment of the polar bears living there. Since the first studies in the 1980s, it has been known that the white giants are very heavily contaminated with environmental toxins. As a final consumer in the food chain, they consume fish, seals and other marine life that also ingested the toxins and ultimately accumulated them in their bodies.

Young polar bears are nursed for 1½ to 2½ years. During this time they learn the mother’s hunting behavior and are eventually abandoned by her. Under the harsh conditions of the Arctic, only about half of the young survive the first five years after birth. (Image: Heiner Kubny)

Jonathan Martin of the University of Alberta in Edmonton and his colleagues have studied how bear pressures have evolved in recent years, using two polar bear populations from Hudson Bay and the Beaufort Sea in the Arctic Ocean as examples. To do this, they analyzed blood serum samples from animals in both groups taken at regular intervals between 1984 and 2014. The evaluation using particularly sensitive chromatographic and mass spectrometric methods revealed some surprises. In total, the scientists detected hundreds of chemicals from a total of 13 different substance classes. These included PCBs previously found in polar bears, but also a number of previously unknown PCB metabolites.

The polar bears are also suffering from climate change. With the projected decline in Arctic sea ice, up to 2/3 of the current polar bear population is expected to be lost by the mid-21st century. (Image: Heiner Kubny)

In addition, Martin and his team discovered for the first time so-called perfluorinated alkyl sulfonic acids (PFSAs) in polar bear serum, including perfluorinated alkyl ether sulfates. These substances can have a negative effect on the reproduction and development of living beings, but are still used industrially in some cases despite health concerns.

Alarmingly, the researchers found that polar bear exposure to PFSAs actually increased steadily between 1984 and 2014. Animals from the Beaufort Sea were particularly affected. The likely reason: they live closer to China’s major industrial regions, which continue to release the chemicals into the environment on a large scale. According to them, the unexpected increase in some environmental toxins in particular is a cause for concern. It shows that current regulations and bans do not go far enough: “Endangered animal species are accumulating more and more of these substances even at the outposts of the earth, such as in the Arctic Ocean,” the team states.

Heiner Kubny, PolarJournal

Print Friendly, PDF & Email
error: Content is protected !!
Share This